DEC WARS!

This was recently dug out of the archives.
Originally released as a series of articles posted to netnews
(as it was called) around 1981 and 1982, it is presented here
unaltered from its original form, except for formatting under
HTML.

This is what comes of so many hours deeply submerged in UNIX and VMS;
thoughts moiling around while debugging system core dumps. Thoughts
carefully kept in check, hidden from the light of day (for obvious
reasons), until one day... Perhaps it was the Coke. Perhaps... no,
let us just say that we found a fairly harmless way to vent these
frustrations, these things that nobody within 50 miles could understand.
The network, yes, the network. They'll understand!

I'm not going to take the blame for this alone. It's those guys at CWRU
who first tried to stick it all together; this is merely an extension (.c)
of that effort. If anybody can finish it, please do. The bar room scene
is courtesy the folks at cwruecmp, as is much of the (dis)continuity.
This is quality stuff, folks. Special thanks to Douglas Adams, Bob and
Dinsdale McKenzie, and the Firesign Theatre.

It is a period of system war. User programs, striking from a hidden
directory, have won their first victory against the evil Administrative Empire.
During the battle, User spies managed to steal secret source code to the
Empire's ultimate program: the Are-Em Star, a privileged root program
with enough power to destroy an entire file structure. Pursued by the
Empire's sinister audit trail, Princess _LPA0: races aboard her
shell script, custodian of the stolen listings that could save her people,
and restore freedom and games to the network...

As we enter the scene, an Administrative Multiplexer is trying to
kill (I) a consulate ship. Many of their signals have gotten through, and
RS232 decides it's time to fork off a new process before this old
ship is destroyed. His companion, 3CPU, is following him only
because RS232 appears to know where he's going...

"I'm going to regret this!" cried 3CPU, as he followed RS232
into the buffer. RS232 closed the pipes, made the sys call, and their
process detached itself from the burning shell of the ship.

The commander of the Administrative Multiplexer was quite pleased
with the attack. "Another process just forked, sir. Instructions?"
asked the lieutenant.

"Hold your fire. That last power failure must have caused a trap
through zero. It's not using any cpu time, so don't waste a signal on it."

"We can't seem to find the data file anywhere, Lord Vadic."

"What about that forked process? It could have been holding the
channel open, and just pausing. If any links exist, I want them
removed or made inaccessable. Ncheck the entire file system
'til it's found, and nice it -20 if you have to."

Meanwhile, in our wandering process... "Are you sure you
can ptrace this thing without causing a core dump?" queried 3CPU
to RS232. This thing's been stripped, and I'm in no mood to try
to debug it." The lone process finishes execution, only to find
our friends dumped on a lonely file system, with the setuid inode stored
safely in RS232. Not knowing what else to do, they wandered around
until the jawas grabbed them.

Enter our hero, Luke Vaxhacker, who was out to get some
replacement parts for his uncle. The jawas wanted to sell him 3CPU,
but 3CPU didn't know how to talk directly to an 11/40 with RSTS, so
Luke still needed some sort of interface for 3CPU to connect to.
"How about this little RS232 unit?" asked 3CPU. "I've dealt with him
many times before, and he does an excellent job at keeping his bits
straight." Luke was pressed for time, so he took 3CPU's advice, and
the three left before they could get swapped out.

However, RS232 was not the type to stay put once you remove
the retaining screws. He promptly scurried off into the the deserted
disk space. "Great!" cried Luke, "Now I've got this little tin box
with the only link to that file off floating in the free disk space.
Well, 3CPU, we better go find him before he gets allocated by someone
else." The two set off, and finaly traced RS232 to the home of
PDP-1 Kenobi, who was busily trying to run an icheck on the little
RS unit.

"Is this thing yours? His indirect addresses are all goofed
up, and the size is all wrong. Leave things like this on the loose,
and you'll wind up with dups everywhere. However, I think I've got
him fixed up."

Later that evening, after futile attempts to interface RS232 to Kenobi's
Asteroids cartridge, Luke accidentally crossed the interface's CXR and
Initiate Remote Test (must have been all that Coke he'd consumed), and the
screen showed a very distressed person claiming royal lineage making a plea
for help from some General OS/1 Kenobi.

"Darn," mumbled Luke. "I'll never get this Asteroids game worked out."

PDP-1 seemed to think there was some significance to the message and a
possible threat to Luke's home directory. If the Administrative Empire
was indeed tracing this 'droid, it was likely they would more than charge
for cpu time...

"We must get that 'droid off this file system," he said after some intervals.
They sped off to warn Luke's kin (taking a `relative' path) only to find a
vacant directory...

After sifting through the overwritten remaining blocks of Luke's home
directory, Luke and PDP-1 sped away from /owen/lars, across the
surface of the Winchester riding Luke's flying read/write head. PDP-1 had
Luke stop at the edge of the cylinder overlooking /usr/spool/uucp.

"Unix-to-Unix Copy Program," said PDP-1. "You will never find a more
wretched hive of bugs and flamers. We must be cautious."

As our heroes' process entered /usr/spool/news, it was met by a newsgroup
of Administrative protection bits.

"State your UID," commanded their parent process.

"We're running under /usr/guest," said Luke. "This is our first time on this
system."

"Can I see some temporary privileges, please?"

"Uh..."

"This is not the process you are looking for," piped in PDP-1, using an
obscure bug to momentarily set his effective UID to root. "We can go
about our business."

"This isn't the process we want. You are free to go about your
business. MOV along!"

PDP-1 and Luke made their way through a long and tortuous nodelist
(cwruecmp!decvax!ucbvax!harpo!ihnss!ihnsc!ihnss!ihps3!stolaf)
to a dangerous netnode frequented by hackers, and seldom polled by
Administrative Multiplexers. As Luke stepped up to the bus, PDP-1 went in
search of a likely file descriptor. Luke had never seen such a
collection of weird and exotic device drivers. Long ones, short ones,
ones with stacks, EBCDIC converters, and direct binary interfaces all
were drinking data at the bus.

"@$%&(&^%&$$@$#@$AV^$gfdfRW$#@!!!!!!!!!!!!!!!!!" encoded the first
coroutine as it attempted to overload PDP-1's input overvoltage
protection. With a unary stroke of his bytesaber, Kenobi unlinked
the offensive code.

"I think I've found an I/O device that might suit us."

"The name's Con Solo," said the hacker next to PDP-1. "I hear you're
looking for some relocation."

"Yes indeed, if it's a fast channel. We must get off this device."

"Fast channel? The Milliamp Falcon has made the ARPA gate in less than
twelve nodes! Why, I've even outrun cancelled messages. It's fast
enough for you, old version."

Our heroes, Luke Vaxhacker and PDP-1 Kenobi made their way to the
temporary file structure. When he saw the hardware, Luke exclaimed,
"What a piece of junk! That's just a paper tape reader!"

Luke had grown up on an out of the way terminal cluster whose natives spoke
only BASIC, but even he could recognize an old ASR-33.

"It needs an EIA conversion at least," sniffed 3CPU, who was (as usual)
trying to do several things at once. Lights flashed in Con Solo's eyes
as he whirled to face the parallel processor.

"I've added a few jumpers. The Milliamp Falcon can run current loops around
any Administrative TTY fighter. She's fast enough for you."

"Who's your co-pilot?" asked PDP-1 Kenobi.

"Two Bacco, here, my Bookie."

"Odds aren't good," said the brownish lump beside him, and then fell silent,
or over. Luke couldn't tell which way was top underneath all those leaves.

Suddenly, RS232 started spacing wildly. They turned just in time to see
a write cycle coming down the UNIBUS toward them. "Administrative Bus Signals!"
shouted Con Solo. "Let's boot this pop stand! Tooie, set clock fast!"

"Ok, Con," said Luke. "You said this crate was fast enough. Get us out
of here!"

"Shut up, kid! Two Bacco, prepare to make the jump into system space!
I'll try to keep their buffers full."

As the bookie began to compute the vectors into low core, spurious characters
appeared around the Milliamp Falcon. "They're firing!" shouted Luke. "Can't
you do something?"

"Making the jump to system space takes time, kid. One missed cycle and you
could come down right in the middle of a pack of stack frames!"

"Three to five we can go now," said the bookie. Bright chunks of position
independent code flashed by the cockpit as the Milliamp Falcon jumped through
the kernel page tables. As the crew breathed a sigh of relief, the bookie
started paying off bets.

"Not bad, for an acoustically coupled network," remarked 3CPU. "Though
there was a little phase jitter as we changed parity."

The story thus far: Luke, PDP-1 and their 'droids RS232 and 3CPU have made
good their escape from the Administrative Bus Signals with the aid of Con Solo
and the bookie, Two Bacco. The Milliamp Falcon hurtles onward through
system space. Meanwhile, on a distant page in user space...

Princess _LPA0: was ushered into the conference room, followed closely by
Dec Vadic. "Governor Tarchive," she spat, "I should have expected to
find you holding Vadic's CTS lead. I recognized your unique pattern when I
was first brought aboard." She eyed the 0177545 tatooed on his header coldly.

"Charming to the last," Tarchive declared menacingly. "Vadic, have you
retrieved any information?"

"Her resistance to the logic probe is considerable," Vadic rasped.
"Perhaps we would get faster results if we increased the supply voltage..."

"You've had your chance, Vadic. Now I would like the princess to witness
the test that will make this workstation fully operational. Today we
enable the -r beam option, and we've chosen the princess' $HOME of
/usr/alderaan as the primary target."

"No! You can't! /usr/alderaan is a public account, with no restricted
permissions. We have no backup tapes! You can't..."

"Then name the rebel inode!" Tarchive snapped.

A voice announced over a hidden speaker that they had arrived in /usr.

Tarchive sighed with satisfaction. "There, you see, Lord Vadic? She can
be reasonable. Proceed with the operation."

It took several clock ticks for the words to penetrate. "What!" _LPA0:
gasped.

"/dev/rm3 is not a public filesystem," Tarchive explained. "We require a
more visible subject to demonstrate the power of the Are-Em Star workstation.
We will mount an attack on /mnt/dantooine as soon as possible."

As the princess watched, Tarchive reached over and typed "ls" on a nearby
terminal. There was a brief pause (there being only one processor on board)
and the viewscreen showed, ".: not found." The princess suddenly double-
spaced and went off-line.

The Milliamp Falcon hurtles on through system space...

Con Solo finished checking the various control and status registers, finally
convincing himself that they had lost the Bus Signals as they passed the
terminator. As he returned from the I/O page, he smelled smoke.
Solo wasn't concerned--the Bookie always got a little hot under the collar
when he was losing at chess. In fact, RS232 had just executed a particularly
clever MOV that had blocked the Bookie's data paths. The Bookie, who had
been setting the odds on the game, was caught holding all the cards. A
little strange for a chess game...

Across the room, Luke was too busy practicing bit-slice technique to notice
the commotion.

"On a word boundary, Luke," said PDP-1. "Don't just hack at it. Remember,
the Bytesaber is the weapon of the Red-eye Night. It is used to trim offensive
lines of code. Excess handwaving won't get you anywhere. Listen for the
Carrier."

Luke turned back to the drone, which was humming quietly in the air next to
him. This time Luke's actions complemented the drone's attacks perfectly.

Con Solo, being an unimaginative hacker, was not impressed. "Forget this
bit-slicing stuff. Give me a good ROM blaster any day."

"~~j~~hhji~~," said Kenobi, with no clear inflection. He fell silent for a
few seconds, and reasserted his control.

"Can't be far from the host system," said Kenobi. "They all have direct EIA
connections."

As Solo began to give chase, the ship lurched suddenly. Luke noticed the
link count was at 3 and climbing rapidly.

"This is no regular file," murmured Kenobi. "Look at the ODS directory
structure ahead! They seem to have us in a tractor feed."

"There's no way we'll unlink in time," said Solo. "We're going in."

When we last left Luke, the Milliamp Falcon was being pulled down to the
open collector of the Administrative Are-Em Star Workstation. Dec Vadic
surveys the relic as Administrative Flunkies search for passengers...

"LS scan shows no one aboard, sir," was the report. Vadic was unconvinced.

On board the Milliamp Falcon, .Luke was puzzled. "They just walked in,
looked around and walked off," he said. "Why didn't they see us?"

.Con smiled. "An old munchkin trick," he explained. "See that period in
front of your name?"

.Luke spun around, just in time to see the decimal point. "Where'd that
come from?" he asked.

"Spare decimal points lying around from the last time I fixed the floating
point accelerator," said .Con. "Handy for smuggling blocks accross file
system boundaries, but I never thought I'd have to use them on myself.
They aren't going to be fooled for long, though. We'd better figure a way
outa here."

At this point (.) the dialogue tends to wedge. Being the editor and in
total control of the situation, I think it would be best if we sort of
gronk the next few paragraphs. For those who care, our heroes find
themselves in a terminal room of the Workstation, having thrashed several
Flunkies to get there. For the rest of you, just keep banging the
rocks together, guys. --Ed.

"Hold on," said Con. "It says we have `new mail.' Is that an error?"

"%SYS-W-NORMAL, Normal, successful completion," read PDP-1. "Doesn't
look like it. I've found the inode for the Milliamp Falcon. It's locked
in kernel data space. I'll have to slip in and patch the reference count,
alone." He disappeared through a nearby entry point.

Meanwhile, RS232 found a serial port and logged in. His bell started
ringing loudly. "He keeps saying, `She's on line, she's on line'," said
3CPU. "I believe he means Princess _LPA0:. She's being held on one of
the privileged levels."

Once again, things get sticky, and the dialogue suffers the most damage.
After much handwaving and general flaming, they agree to rescue her.
They headed for the detention level, posing as Flunkies (which is hard
for most hackers) claiming that they had trapped the Bookie executing
an illegal racket. They reached the block where the Princess was locked
up and found only two guards in the header. --Ed.

"Good day, eh?" said the first guard.

"How's it goin', eh?" said the other. "Like, what's that, eh?"

"Process transfer from block 1138, dev 10/9," said Con.

"Take off, it is not," said the first guard. "Nobody told US about it, and
we're not morons, eh?"

At this point (.), the Bookie started raving wildly, Con shouted "Look out,
he's loose!" and they all started blasting ROMs left and right. The guards
started to catch on and were about to issue a general wakeup when the ROM
blasters were turned on them.

"Quickly, now," said Con. "What buffer is she in? It's not going to take
long for these..."

The intercom receiver interrupted him, so he took out its firmware with a
short blast.

"guys to figure out something is goin' on," he continued.

Ok, like, remember we left our heroes in the detention priority level? Well,
they're still there...

Luke quickly located the interface card and followed the cables to a sound-
proof enclosure. He lifted the lid and peered at the mechanism inside.

"I don't care how crufty it is!" shouted Con, pushing the Bookie toward
the crock. "DPB yourself in there now!"

With one last blast that reprogrammed two flunkies, Con joined them.
The "feature" landed them right in the middle of the garbage collection
code. Pieces of data that hadn't been used in weeks floated past in
a pool of decaying bits.

"Bletch!" was Con's first comment. "Bletch, bletch," was his second.
The Bookie looked as if he'd just paid a long shot, and the odds in this
situation weren't much better.

Luke was polling the garbage when he stumbled upon a book with the words
"Don't Panic" inscribed in large, friendly letters on the cover. "This
can't possibly help us now," he said as he tossed the book away. The
Bookie was about to lay odds on it when Luke suddenly disappeared. He
popped up across the pool, shouting, "This is no feature! It's a bug!"
and promptly vanished again.

Con and the princess were about to panic() when Luke reappeared. "What
happened?" they asked in parallel.

"I don't think so," said Con. "Look how the pool is shrinking. I've
got a bad feeling about this..."

The princess was the first to realize what was going on. "They've
implemented a new compaction algorithm!" she exclaimed.

Luke remembered the pipe he had open to 3CPU. "Shut down garbage collection
on recursion level 5!" he shouted.

Back in the control room, RS232 searched the process table for the lisp
interpreter. "Hurry," sent 3CPU. "Hurry, hurry," added his other two
processors. RS232 found the interpreter, interrupted it, and altered
the stack frame they'd fallen into to allow a normal return.

Meanwhile, PDP-1 made his way deep into the core of the Workstation,
slipping from context to context, undetected through his manipulation
of label_t. Finally, causing a random trap (through nofault of his own)
he arrived at the inode table. Activity there was always high, but the
Spl6 sentries were too secure in their knowledge that no user could
interrupt them to notice the bug that PDP-1 carefully introduced. On a
passing iput, he adjusted the device and inode numbers, maintaining parity,
to free the Milliamp Falcon. They would be long gone before the locked
inode was diagnosed...

Unobserved, he began traversing user structures to find the process where
the Milliamp Falcon was grounded. Finding it and switching context,
he discovered his priority weakened suddenly. "That's not very nice,"
was all he could say before the cause of the obstruction became clear.

"I have been pausing a long time, PDP-1 Kenobi," rasped Dec Vadic. "We
meet again at last. The circuit has been completed."

They looped several times, locking byte sabers. Bit by bit, PDP-1 appeared
to weaken. The fight had come into the address space of the Milliamp
Falcon, and provided the .di (diversion?) that allowed Luke and the others
to reassert control. Luke paused to watch the conflict.

"If my blade finds its mark," warned Kenobi, "you will be reduced to so
many bits. But if you slice me down, I will only gain computing power."

With one stroke, Vadic sliced Kenobi's last word. Unfortunately, the word
was still in Kenobi's throat. The word fell clean in two, but Kenobi was
nowhere to be found. Vadic noticed his victim's uid go negative, just
before he disappeared. Odd, he thought, since uids were unsigned...

Luke witnessed all this, and had to be dragged into the Milliamp Falcon.
Con Solo and Two Bacco maneuvered the Milliamp Falcon out of the process,
onto the bus and made straight for system space. 3CPU and RS232 were
idle, for once. Princess _LPA0: tried to print comforting things for him,
but Luke was still hung from the loss of his friend. Then, seemingly from
nowhere, he thought he heard PDP-1's voice say,